Log-turning device



Jan. 13, 1970 M. J. HANSON 3,

LOG NNNNNNNNNNNN CE Filed April 50, 1968 s Sheets-Sheet 1 INVENTORMARSHALL J. HANSON ATTORNEYS Jan; 13, 1970 M. J. HANSON LOG-TURNINGDEVICE 5 Sheets-Sheet 2 Filed April 30, 1968 INVENTOR MARS HALL J.HANSON 351M 00, J m en a morz tgiyv zagow ATTORNEYS Jan. 13, 1970 M. J.HANSON 3,489,188

LOG-TURNING DEVICE Filed April 30, 1968 3 Sheets-Sheet 5 INVENTORMARSHALL J. HANS ON ATTORNEYS United States Patent O U.S. Cl. 143102 7Claims ABSTRACT OF THE DISCLOSURE A log-turning device is provided forturning logs on a sawmill carriage. The device includes a toothedendless chain slidably mounted around the periphery of a first lever armthat is pivotally Connected to the sawmill carriage. A second lever armis pivotally connected tothe carriage at one end and to the chain at theother end, so that pivotal movement of the second arm pushes the firstarm about its axis into engagement with a log on the carriage andsimultaneously slides the toothed chain around the first arm to turnthelog on the carriage.

This invention relates to a log-turning device for sawmills, and moreparticularly to a device for turning logs on a sawmill carriage whilethe carriage is in motion.

In a sawmill, logs to be cut are generally supported on a reciprocatingcarriage that feeds the logs along the saw line to the saw and thenreturns to its starting position After a section has been cutlongitudinally from one face of the log, the log is turned about itsaxis to present an other face to the saw so that a further section canbe cut from the log.

In the past, the logs have been turned by first returning the carriage'to its initial position, pushing the log off the carriage onto a log.deck, where a nigger turns the log three-fourths of a turn to place thecut side down, and then returning the log to the carriage. Valuableoperating time is thus lost in this method of operation because the millnecessarily remains idle for substantial periods of time while theoperators are performing the required turning operation. I It istherefore a primary object of this invention-to provide a new andimproved log-turning device that turns the logs on the carriage While itis in motion, whereby the log-turning operation is greatly simplifiedand expedited, resulting in a more efiicient operation of the sawmill.

Another object of this invention'is to provide a logturning device thatis simple and rugged in construction, highly efficient in operation, andthat can be readily installed on existing sawmill carriages.

Additional objects and advantages of this invention will be set forth inthe description which follows, and in part will. be obvious from thedescription or may be learned by practice of the invention, the objectsand advantages being realized and attained by means ofthe machines,instrumentalities, devices, and combinations particularly pointed out inthe appended claims.

To achieve the foregoing objects and in accordance with its purpose,this invention, as embodied and broadly described, comprises a devicefor turning logs on a sawmill carriage, in which the carriagereciprocates in a direction parallel to the saw line of a saw between alog-charging position and a log-cutting position.

The device includes a first arm to be pivotally connected to thecarriage on an axis parallel to the saw line. A chain havinglog-engaging means spaced at intervals along the chain is slidablymounted around the periphery of the 3,489,188 Patented Jan. 13, 1970 icefirst arm. Advancing means pivotally connected to the chain are furtherprovided for rotating the first arm about its axis into engagement withthe log and simultaneously for advancing the chain around the first armto bring the log-engaging means into contact with the log and turn it onthe carriage.

In accordance with the invention, the device turns the log one-fourth A)turn on the carriage after each cut to place the cut side down andpresent a new log face to the saw. Preferably the device turns the logwhile the carriage is in motion and returning to the log-chargingposition; so that the carriage can be immediately reversed and returnedto the log-cutting position.

In accordance with a preferred embodiment of this invention, theadvancing means comprises a second arm to be pivotally connected at oneend to the carriage on an axis parallel to and spaced from the first armaxis and at the other end to the chain, and actuating means for pivotingthe second arm about its axis in a direction towatdthe first arm to pushthe first arm into engagement with the log and simultaneously to advancethe chain around the first arm.

The accompanying drawings which are incorporated in and constitute apart of this specification, illustrate an embodiment of the invention,and together with the descriptioh, serve to explain the principles ofthis invention.

Of the drawings:

FIG. 1 is a perspective view of a sawmill carriage having thelog-turning device of this invention applied thereto;

FIG. 2 is a side elevation showing, in solid lines, the log-turningdevice of this invention in an at-rest position; and in phantom lines,the device in an extended and operating position;

FIGS. 3 and 4 are schematic views showing the turning of a log with thelog-turning device of this invention;

FIG. 5 is a sectional view taken along the line' 55 of FIG. 2; and

FIG. 6 is a left-side view of the device shown in FIG. 2, with the chainremoved for clarity.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and'e'xplanatory, butare not restrictive of the invention.

Reference will now be made in detail to the present preferred embodimentof the invention,'an example of which is illustrated in the accompanyingdrawings.

Logs are conventionally stockpiled on an inclined deck '(not shown) andthen fed in sequence onto a reciprocating sawmill carriage 10 that holdsand supports the logs while they are being cut. As shown in FIG. 1, alog to be cut is supported on carriage 10 by slides 14, positioned by aplurality of knees '16, and securely held in place by clamps 18. Theknees and clamps are adjustable across the'carriage by suitable means 19so that the log can be advanced towards orwithdrawn from the saw lineofa saw blade (-not shown) to allow the desired thickness of cut to bemade in the log. i

The-carriage is then advanced along rails '20 ina direction'parallelto'the saw line, as shown by arrow 22, toward the saw to cut a sectionorboard longitudinally from one face of the log. 1 As shown in FIG. 1,the present invention provides a simplified log-turning device,generally indicated as' 24, for turning logs on sawmill carriage 10, andmore par ticularly to a'device forturning a log one-fourth (V4) turn onthe carriage aftera cut has been made in the log. As best shown in FIG.2, log-turning device 24 includes a first lever arm 34 having a crankarm 36 pivotally mounted to sawmill carriagelfl about axis '38 below thesupporting surface of slides 14. Extending around 1 the periphery of arm34 is a rail 40 (see FIG. for supporting and guiding a chain 42. Chain42 is conventional, comprising links 44 and rollers 46, the rollersrunning along the surface of rail 40, while the inside surfaces 48 oflinks 44 guide the chain along the rail.

In accordance with the invention, chain 42 has a plurality oflog-engaging means spaced at intervals along the length of the chain toengage and rotate the log about its axis while the log is on thecarriage. As embodied and as shown in FIG. 2, the log-engaging meansincludes a plurality of spaced dogs 50 having a leading edge 52 thatinclines forwardly to provide a barb or tooth 54 that will bite into theperiphery of the log and rotate it about its axis. Dogs 50 may form anintegral part of links 44 or may be attached to the existing links of aconventional chain.

In accordance with the invention, advancing means are further providedto rotate lever arm 34 about axis 38 and bring it into engagementwith alog while simultaneously advancing chain 42 around the periphery of thearm. As embodied and as shown in FIG. 2, this means includes a slide 56that is connected to chain 42 and slidably mounted along the undersideof arm 34. The advancing means also includes a second lever arm 70 thatis pivotally connected to slide 56 at 72 and to carriage about axis 74,the second arm axis being parallel to and spaced from first arm axis 38.

As best shown in FIG. 5, slide 56 has a T-shaped crosssection andincludes surfaces 58 that slide along abea'ring plate 60 on theunderside of arm 34, and a groove 62 complementary with rail 40 to guidemovement of the slide along the arm. A plurality of gussets 64 areprovided to strengthen bearing plate 60 with respect to arm 34. Aplurality of holes 73 are further provided in slide 56 to permitadjustment of the pivotal connection between arm 70 and the slide.

Actuating means are provided to rotate arm 70 about its axis toward arm34. As embodied, this means comprises a double-acting pneumatic cylinder78 having a push rod 78 pivotally connected to lever arm 70 at 80 forraising and lowering the log-turning device in accordance with theobjects of this invention.

In operation, pneumatic cylinder 76 is actuated and rotates lever arm 70in a counterclockwise direction toward lever arm 34. As shown in FIG. 2,rotary movement of arm 70 pushes upwardly on slide 56 and lever arm 34,causing arm 34 to rotate about axis 38 in a counterclockwise direction,as shown by arrow 82, and into engagement with a log on the carriage.Simultaneously, slide 56 is being moved along bearing plate 60 on theunderside of arm 34 which causes chain 42 to advance around theperiphery of the arm in a clockwise direction and dogs 50 to bite intothe periphery of the log. Pneumatic cylinder 76 continues to pushupwardly on arm 70 until the device reaches its most extended position,as shown in phantom in FIG. 2.

In operation of a sawmill utilizing the turning device of thisinvention, and as best shown in FIGS. 3 and 4, an uncut log 84 is placedon slides 14 of carriage 10 and is accurately positioned thereon byknees 16 so that the face of the log is adjacent saw line 86. Theoperator then lowers clamps 18 to securely hold the log against theknees and advances the carriage to the sawing position removing a boardfrom one face of the log along line 86.

After the log has been cut, the carriage is returned to its initialposition, clamps 18 withdrawn to an out-of the-way position, and knees16 receded slightly, as shown in FIG. 4, to facilitate turning of thelog. During the return movement of the carriage, the operator orsuitable machine cycling means activates pneumatic cylinder 76 causinglever arm 34 to rotate upwardly and into engage ment with log 84 whilesimultaneously advancing chain 42 around the periphery of arm 34 in aclockwise direc- 4 tion. As shown in FIG. 4, dogs 50 on'chain 42 biteinto the lower part of log 84 raising it upwardly and causing it to turnabout its axis in the direction of arrow 88.

Operation of the log-turning device is continued until the log hasturned through and the previously cut side is now facedown on thecarriage. Log-turning device 24 is then lowered, knees 16 advanced toaccurately position a new face of the log with respect to saw line 86,and clamps 18 again lowered to hold the log on the carriage. The sawingand the turning operations are repeated until the log has turned througha total of 270 to provde a log having all four faces removed therefrom.

It will therefore be apparent from the foregoing description that thedevice of this invention effectively turns the log on the carriage whilethe carriage is in motion and returning to its starting or log-chargingposition. The device, therefore, relieves the operator of a great amountof time and efiort that was previously required to perform this turningoperation, thereby drastically increasing the efiiciency and economy ofthe entire cutting operation.

It will also be appreciated that with the device of this invention aseparate log-turning device on the log deck as heretofore used is notrequired to turn the log. Without departing from the scope of thisinvention, however, suitable means such as a conventional nigger orrestraining arm, can be provided on the log deck to push the log backagainst the knees after it has been turned with the device of thisinvention in the event that it does not fall in the proper place due toit being out-of-round or having protruding stubs left over from removedbranches.

The invention in its broader aspects is not limited to the specificdetails shown and described, and departures may be made from suchdetails Within the spirit and scope of the accompanying claims withoutdeparting from the principles of the invention and without sacrificingits chief advantages.

What is claimed is:

1. A device for turning logs on a sawmill carriage which is reciprocatedbetween a log-charging position and a log-cutting position in adirection parallel to the saw line of a saw comprising:

(a) a first arm to be pivotally connected to the carriage on an axisparallel to the saw line;

(b) a chain slidably mounted around the periphery of the first arm;

(c) a plurality of log-engaging means spaced at intervals along thechain; and

(d) advancing means pivotally connected to the chain for rotating thefirst arm about its axis into engagement with a log on the carriage andsimultaneously for advancing the chain around the periphery of the armto bring the log-engaging means into contact with the log and turn it onthe carriage.

2. The device of claim 1, wherein the advancing means comprises a secondarm to be pivotally connected at one end to the carriage on an axisparallel to and spaced from the first arm axis and at the other end tothe chain and actuating means for pivoting the second arm about its axisin a direction toward the first arm to push the first arm intoengagement with the log and simultaneously to advance the chain aroundthe first arm.

3. The device of claim 2, wherein the actuating means for rotating thesecond arm comprises a pneumatic cylinder.

4. The device of claim 2, wherein the log-engaging means comprises aplurality of dogs mounted at intervals along the length of the chain.

5. The device of claim 2, including a slide slidably mounted along oneside of the first arm and connected to opposite ends of the chain and tothe second arm, whereby pivotal movement of the second arm pushes thefirst arm about its axis and simultaneously advances the slide along thefirst arm to advance the chain around th periphery of the first arm.

6. The device of claim 5, which includes adjustment 6 means for alteringthe location of the connection between References Cited the slide andthe second arm.

7. The device of claim 2, in combination with the UNITED sljATEs PATENTScarriage for supporting a log to be sawed, 'wherein said 1,252,894 1918Fltzgel'ald X first and second arms are pivotally connected to the2,988,117 4/1959 Lambsofl carriage below the level of the log supportedby the car- 5 riage so that pivotal movement of the second arm bringsANDREW JUHASZ, Pnmary Exammef the first arm and the log-engaging means pinto engage- JAMES F. COAN, Assistant Examiner ment with the undersideof the log.

